GISTs comprise less than 1% of all gastrointestinal (GI) tumors but are the most common mesenchymal tumors of the GI tract.[1-3] There are estimated to be over 6,000 new GIST cases per year in the United States, with an age-adjusted yearly incidence of 6.78 per million from 2001 to 2011. GISTs can affect patients of all ages but are most predominant in older adults (median age, 65–69 years).[4,5] Globally, GISTs affect men and women with equal frequency. Geographically, GISTs are most prevalent in China (Shanghai), Taiwan, Korea, and Norway.[5] In the United States, GISTs are more commonly diagnosed in Black Americans (13.7 per million) and Asian or Pacific Islander Americans (11 per million) than in White Americans (6.5 per million).[4]
The true incidence is not known, in part, because small indolent GISTs (i.e., <1 cm) are either not clinically apparent or are not included in cancer registries.[5-7]
Most GISTs are sporadic, but there are rare familial forms associated with neurofibromatosis type 1 (NF1) or heritable mutations in KIT and SDH.[2,3] GISTs rarely affect children and young adults (<1% of cases), with a median age of 15 years in cases that are nearly always associated with an underlying genetic predisposition.[8,9] For more information, see Childhood Gastrointestinal Stromal Tumors Treatment.
GISTs can occur anywhere along the GI tract, but most often are found in the stomach or small intestine. The American Joint Committee on Cancer (AJCC) Cancer Staging Manual lists the following approximate distributions:[10]
GISTs range in size from less than 1 cm to more than 40 cm, with an average size of approximately 5 cm when diagnosed clinically. They typically arise within the muscle wall of the GI tract.[11] Small GISTs may form solid subserosal, intramural, or, less frequently, polypoid intraluminal masses. Large tumors tend to form external masses attached to the outer aspect of the bowel wall involving the muscular layers.[11]
The clinical presentation of patients with GISTs varies depending on the following:[12,13]
The signs and symptoms of GISTs include the following:
Smaller lesions may be found incidentally during surgery, radiological studies, or endoscopy. The natural history of these incidental tumors and the frequency of progression to symptomatic disease are unknown. There may be a substantial reservoir of small GISTs that do not progress to symptomatic stages.
Common sites of metastasis include the liver and peritoneal dissemination within the abdominal cavity. In adults, lymph node involvement and spread to the lungs or other extra-abdominal sites is unusual.[14]
Rare paraneoplastic consumptive hypothyroidism (from overexpression of a thyroid-inactivating enzyme) has been reported in a few patients.[15]
Pediatric GISTs are typically associated with germline SDH loss. The clinical behavior is distinct with typically a gastric location, more indolent course, multifocal presentation, and lymph node metastases. Germline SDH loss is also associated with hereditary kidney cancer, paragangliomas, and other tumors.[16,17]
GISTs should be included in the differential diagnosis of any intra-abdominal nonepithelial malignancy. Standard diagnostic interventions may include the following:[12]
Endoscopic ultrasound with fine-needle aspiration (FNA) biopsy is useful in the diagnosis of GISTs in the upper GI tract, as most tumors arise below the mucosal layer and grow in an endophytic fashion. Endoscopic ultrasound–guided FNA biopsy is preferred to percutaneous biopsy, given the risk of tumor hemorrhage and peritoneal dissemination.[12,18,19] For localized resectable GISTs with classic imaging findings, some surgeons proceed directly to surgery without biopsy.
Prognostic factors for nonmetastatic GISTs include the following:
Approximately 20% to 25% of gastric GISTs and 40% to 50% of small intestinal GISTs are clinically aggressive.[13,20] It is estimated that approximately 10% to 25% of patients present with metastatic disease.[14,20] For nonmetastatic GISTs, the key parameters that impact the risk of recurrence or metastasis include mitotic index (mitoses per 50 high-power fields), tumor size, and tumor location (see Table 1).[11,21-25]
It is also recognized that tumor rupture markedly worsens recurrence-free survival.[26-28] In addition, tumor appearance on CT imaging may predict recurrence risk. Tumors with higher metastatic risk include lobulated or heterogeneously enhancing tumors, as well as those with mesenteric fat infiltration, ulceration, regional lymphadenopathy, or exophytic growth.[29-32]
Mitotic Index (mitoses/HPF) | Size (cm) | Metastasis Rate (%) | Risk of Progressive Disease |
---|---|---|---|
GISTs = gastrointestinal stromal tumors; HPF = high-power field. | |||
aAdapted from Miettinen et al.[25] and Laurini et al.[33] | |||
≤5 per 50 | ≤2 | 0 | None |
>2 to ≤5 | 1.9 | Very low | |
>5 to ≤10 | 3.6 | Low | |
>10 | 12 | Moderate | |
>5 per 50 | ≤2 | 0 | None |
>2 to ≤5 | 16 | Moderate | |
>5 to ≤10 | 55 | High | |
>10 | 86 | High |
Mitotic Index (mitoses/HPF) | Size (cm) | Metastasis Rate (%) | Risk of Progressive Disease |
---|---|---|---|
GISTs = gastrointestinal stromal tumors; HPF = high-power field. | |||
aAdapted from Miettinen et al.[25] and Laurini et al.[33] | |||
≤5 per 50 | ≤2 | 0 | None |
>2 to ≤5 | 1.9–8.5 | Low | |
>5 to ≤10 | 24 | Insufficient data–Moderate | |
>10 | 34–52 | High | |
>5 per 50 | ≤2 | 50–54 | Insufficient data–High |
>2 to ≤5 | 50–73 | High | |
>5 to ≤10 | 85 | High | |
>10 | 71–90 | High |
CT, fluorine F 18-fludeoxyglucose (18F-FDG) PET, and MRI are used to monitor the effects of systemic therapy in patients with unresectable, metastatic, or recurrent disease.[34]
A baseline PET should be performed before tyrosine kinase inhibitor (TKI) therapy in patients who will be monitored for response with 18F-FDG PET. PET imaging may detect the activity of imatinib in GISTs much earlier than CT imaging, with decreased tumor avidity detected as soon as 24 hours after the first dose. Thus, PET may be a useful diagnostic modality for the very early assessment of response to imatinib therapy and for detecting resistance to TKIs.[12]
The optimal modality and frequency for surveillance of metastatic or recurrent disease in patients who have undergone GIST resection has not been studied. Based on the likelihood of recurrence, follow-up recommendations are derived from expert opinion and clinical judgment.
For surgically treated patients with localized disease, routine follow-up schedules may differ across institutions and depend on the risk status of the tumor.[35] Abdominal/pelvic imaging may be performed every 3 to 6 months, but very low-risk lesions may not need to be imaged this frequently.[35]
Gastrointestinal stromal tumors (GISTs) appear to originate from interstitial cells of Cajal (ICC) or their stem cell-like precursors.[1-4] ICC are pacemaker-like intermediates between the gastrointestinal (GI) autonomic nervous system and smooth muscle cells regulating GI motility and autonomic nerve function.[5,6] ICC are located around the myenteric plexus and the muscularis propria throughout the GI tract. ICC or their stem cell-like precursors can differentiate into smooth muscle cells if KIT signaling is disrupted.[7]
GISTs are composed of spindle cells (70%), epithelioid cells (20%), or mixed spindle and epithelioid cells (10%).[8] The histological patterns range from bland-appearing tumors with very low mitotic activity to very aggressive-appearing patterns.[9]
Approximately 85% of GISTs contain oncogenic mutations in one of two receptor tyrosine kinases (RTKs):[10,11]
Constitutive activation of either of these RTKs plays a central role in the pathogenesis of GISTs.[1,12] Tumors without detectable KIT or PDGFRA mutations account for 12% to 15% of all GISTs. Less than 5% of GISTs occur in the setting of syndromic diseases, such as neurofibromatosis type 1 (NF1), Carney triad syndrome (SDH deletion), and other familial diseases.[10,13-15]
Approximately 95% of GISTs are positive for the CD117 antigen, an epitope of KIT RTK expressed by ICC.[10] However, CD117 immunohistochemistry (IHC) is not specific for GISTs and can be seen in other mesenchymal, neural, and neuroendocrine neoplasms.[10] IHC staining for DOG1 helps distinguish GISTs from other mesenchymal tumors, particularly those that are KIT negative.[10,16-18]
Subtypes of GISTs include the following:
A formal staging system for gastrointestinal stromal tumors (GISTs) is available from the American Joint Committee on Cancer (AJCC) Staging Manual. In practice, however, AJCC staging is not routinely implemented when risk assessment is determined by the clinical features noted in the Prognosis section.[1]
The management of patients with gastrointestinal stromal tumors (GISTs) is a multidisciplinary effort involving close collaboration between pathologists, medical oncologists, surgeons, and imaging experts.[1]
Surgical resection is the primary treatment modality for the following types of patients:[2][Level of evidence C2]
Endoscopic surveillance is an option for patients with tumors measuring 2 cm or smaller with a mitotic index of 5 or less per 50 high-power fields. The low rates of progression and metastasis in these tumors make endoscopic surveillance viable in place of surgical resection.[3]
The goal of surgery is complete gross resection with an intact pseudocapsule and negative microscopic margins.[4] Because GISTs are generally encapsulated and relatively less infiltrative than other malignancies, wide excision is not necessary. Lymphadenectomy is typically unnecessary, given that lymph node metastasis is rare with GISTs. However, lymphadenectomy should be considered in patients with SDH-deficient GISTs and pathologically enlarged lymph nodes.
If anatomically feasible, laparoscopic surgery is increasingly performed instead of laparotomy. Reports demonstrate lower rates of recurrence, shorter hospital stays, and lower morbidity.[5-8]
Neoadjuvant imatinib therapy can be given to patients with large tumors or difficult-to-access GISTs that are considered marginally resectable. Significant tumor shrinkage is often seen with targeted therapy, so this approach can potentially avoid major organ resection, or enable organ-sparing surgery. Genetic sequencing may be considered to identify sensitive or resistant mutations prior to neoadjuvant imatinib therapy.
For patients with oligometastatic recurrences (e.g., isolated intra-abdominal implants or solitary liver lesions), surgical resection may be used in conjunction with tyrosine kinase inhibitors (TKIs).[9,10][Level of evidence C1] This should only be considered after multidisciplinary consultation.
There is universal agreement that standard chemotherapy has no role in the primary therapy of GISTs.[4,11,12]
Before the advent of molecularly targeted therapy with TKIs, efforts to treat GISTs with conventional cytotoxic chemotherapy were essentially futile.[1] The extreme resistance of GISTs to chemotherapy may be partly caused by the increased expression of P-glycoprotein, the product of the MDR-1 gene, and MRP1, which are cellular efflux pumps that may prevent chemotherapeutic agents from reaching therapeutic intracellular concentrations in GIST cells.[1,13]
TKIs work by inhibiting aberrantly functioning KIT or PDGFRA receptor tyrosine kinases and inducing rapid reduction in tumor growth. TKI therapy is indicated for patients with unresectable, borderline resectable, metastatic, or recurrent GISTs. It is also indicated as adjuvant therapy for patients with GISTs at high risk of recurrence.
The TKI imatinib mesylate is used as first-line therapy for most patients with KIT- and PDGFRA-mutant GISTs.[14] For patients with GISTs characterized by a PDGFRA D842V mutation, avapritinib is used as first-line therapy, given the high clinical benefit and imatinib-resistance in this subtype.[15] Other TKI agents approved for subsequent lines of therapy in patients with KIT/PDGFRA-mutant GISTs include sunitinib, regorafenib, and ripretinib. Additional TKI agents that are occasionally given include nilotinib, sorafenib, and pazopanib.
Imatinib is not typically given to patients with KIT/PDGFRA wild-type GISTs (i.e., SDH-deficient or neurofibromatosis type 1 [NF1]-related GISTs) because of high rates of resistance. Other TKIs (i.e., sunitinib or regorafenib) may have some activity, but most patients are recommended to consider enrolling in clinical trials, if eligible.
For more information on the efficacy, safety, and management of toxicity of imatinib, or additional agents in the setting of imatinib resistance or intolerance, see the Treatment of Resectable Primary GISTs, Treatment of Unresectable Primary GISTs, and Treatment of Metastatic or Recurrent GISTs sections.
Radiation therapy rarely has a role in the management of patients with GISTs. It may occasionally be used for palliation of painful metastases or for patients with unresectable bleeding tumors.[1]
Treatment options for resectable primary gastrointestinal stromal tumors (GISTs) include the following:
All GISTs measuring 2 cm or larger are typically surgically resected. The management of incidentally encountered GISTs measuring smaller than 2 cm remains controversial. There is no evidence for re-excision in patients with a complete resection of all macroscopic disease but microscopically positive margins. Watchful waiting and adjuvant imatinib therapy may be appropriate for these patients.[1,2]
In general, gastric GISTs may be removed by laparoscopic wedge resection, when technically feasible. GISTs rarely involve the locoregional lymph nodes. Thus, extensive lymph node dissection is not indicated unless there is clinically apparent nodal involvement. These tumors may have fragile pseudocapsules, so care must be taken to avoid rupturing the pseudocapsule during surgery, which could result in peritoneal dissemination.
Results from three phase III studies support the use of postoperative adjuvant imatinib for patients with completely resected localized GISTs who have a high risk of recurrence based on tumor size, tumor location, mitotic index, and presence of tumor rupture.[3-10]
Evidence (phase III studies of postoperative imatinib):
The recommended length of adjuvant treatment remains unknown. However, based on the SSG XVIII study results, at least 3 years of therapy is generally used in practice. It is important to note that evidence suggests that, instead of being cytotoxic, imatinib may suppress GIST growth. Therefore, recurrence may be delayed by the suppression of undetectable metastatic disease.[5,11-13] For example, the rate of recurrence increased within 6 to 12 months of discontinuing adjuvant imatinib in both the 1-year and 3-year arms in the SSG XVIII trial.[5] This concept has led to higher-risk patients being given imatinib indefinitely, although there is no direct trial evidence to support that.
Most patients initiate imatinib therapy at a dosage of 400 mg per day. Molecular genotyping of patients with GISTs is recommended as it can impact the use of adjuvant imatinib, as well as the optimal dose. Patients whose tumor harbors a KIT exon 9 mutation may benefit from higher-dose imatinib (800 mg per day) based on data in the metastatic setting.[14] Patients with KIT/PDGFRA wild-type GISTs (i.e., SDH-deficient and neurofibromatosis type 1 [NF1]-related GISTs) or PDGFRA D842V-mutant GISTs are unlikely to benefit from adjuvant imatinib therapy.[5]
Although not fully conclusive, there is some phase II evidence to support continuing adjuvant imatinib therapy for 5 years or more.
Evidence (phase II studies of postoperative imatinib):
Use our advanced clinical trial search to find NCI-supported cancer clinical trials that are now enrolling patients. The search can be narrowed by location of the trial, type of treatment, name of the drug, and other criteria. General information about clinical trials is also available.
Treatment options for unresectable primary gastrointestinal stromal tumors (GISTs) include the following:
Until surgical therapy is feasible, which can take as long as 6 to 12 months, therapy with neoadjuvant imatinib may be used for patients with very large primary GISTs or poorly positioned small GISTs (considered unresectable without the risk of significant morbidity or functional deficit, such as needing a formal gastrectomy, pancreatectomy, or other major organ resection).[1,2] Neoadjuvant imatinib therapy in patients with GISTs is supported by the early results of two phase II studies in the United States [3] and Asia [4], as well as several case series and small retrospective reports.[2,5-10] Neoadjuvant imatinib may be particularly beneficial in rectal GISTs given the large bulky nature of the disease and the extensive surgery required for complete resection.[11,12]
Evidence (phase II studies of neoadjuvant imatinib):
If a preoperative TKI is planned, a biopsy for diagnosis confirmation and, potentially, molecular profiling should be considered. Mutational analysis may help to exclude nonsensitive mutations before starting imatinib cytoreduction therapy. Biopsy and molecular profiling may also determine whether a tumor harbors a KIT exon 9 mutation, which may require an increase in initial imatinib dosing.[1,13] Neoadjuvant imatinib is not used for patients with GISTs harboring a PDGFRA D842V mutation. Some guidelines, such as those from the European Society of Medical Oncology, recommend considering neoadjuvant avapritinib.[14] However, avapritinib has not been tested or validated in the neoadjuvant setting. In addition, patients with KIT/PDGFRA wild-type GISTs (i.e., SDH-deficient or neurofibromatosis type 1 [NF1]-related GISTs) would not benefit from neoadjuvant therapy and should proceed directly to surgery, if feasible.
If indicated, neoadjuvant imatinib is initiated at 400 mg per day in most patients. Patients with KIT exon 9–mutated GISTs may be offered a higher dose (800 mg per day) based on data from the advanced setting.[15] Follow-up imaging, with either computed tomography (CT) or positron emission tomography (PET)-CT, is performed at close intervals. PET-CT can be particularly helpful in assessing initial early response if baseline molecular profiling was not done before neoadjuvant therapy.[16] The optimal duration of neoadjuvant treatment is unknown and should be individualized based on multidisciplinary discussion. Neoadjuvant TKI therapy precludes the ability to risk stratify after surgical resection. Therefore, patients should continue imatinib after surgery for at least 3 total years.
Use our advanced clinical trial search to find NCI-supported cancer clinical trials that are now enrolling patients. The search can be narrowed by location of the trial, type of treatment, name of the drug, and other criteria. General information about clinical trials is also available.
Treatment options for metastatic or recurrent gastrointestinal stromal tumors (GISTs) include the following:
The primary treatment of patients with metastatic or recurrent GISTs involves medical therapy with a TKI. In select cases, surgical therapy may be added. Patients with metastatic or recurrent tumors that do not respond to these measures may be candidates for clinical trials.
Therapy with imatinib is the standard first-line treatment for most patients with metastatic or recurrent disease. The initial dose is 400 mg daily, except for patients with tumors containing KIT exon 9 mutations, who may receive 800 mg daily.[1] The only exception is for patients with GISTs characterized by the PDGFRA D842V mutation. In this subtype, avapritinib is used as first-line therapy given high clinical benefit and imatinib resistance.[2] Most patients can initiate imatinib empirically while awaiting confirmation of their tumor’s molecular profile. That profile may necessitate an imatinib dosing change (i.e., KIT exon 9), a change to avapritinib (i.e., PDGFRA D842V mutation), or indicate likelihood for TKI resistance (i.e., SDH-deficient or neurofibromatosis type 1 [NF1]-related GISTs).
All patients receiving TKI therapy are closely monitored for tumor response and side effects, which may require dose reductions, interruptions, or cessation of TKI therapy in cases of persistent, excessive toxicity. In addition, dose modification of the TKI or substitution with medications that do not affect cytochrome P450 isoenzyme 3A4 (CYP450 3A4) levels may be necessary for patients taking drugs that affect CYP450 3A4 levels.[3]
Response is evaluated with computed tomography (CT), magnetic resonance imaging (MRI), or fluorine F 18-fludeoxyglucose positron emission tomography (18F-FDG PET).[3-7] Treatment is usually continued indefinitely in the absence of disease progression or unacceptable toxicity, with a median time to progression of 24 to 40 months and median survival approaching 45 to 60 months.[3,8-14] A cohort of patients from early imatinib trials have continued on therapy with long-term survival. In a multivariable analysis, age younger than 60 years, performance status 0, smaller size of the largest lesion, and exon 11 KIT mutation were significant prognostic factors for the probability of surviving beyond 10 years.[10] A similar finding for exon 11 was seen in a phase II study.[9]
Evidence (imatinib therapy):
In the event of tumor progression in patients without KIT exon 9 mutations on lower dose imatinib (i.e., 400 mg daily), the imatinib dosage may be increased to 800 mg daily (in split doses). Alternatively, in the management of imatinib resistance, the patient may be switched directly to sunitinib.[23]
The most common toxicities associated with imatinib therapy, all of which may improve with prolonged treatment, include the following:[6,11,24-26]
There are rare reports of heart failure related to imatinib use,[27] primarily in patients with preexisting heart disease. No excess cardiac toxicity was noted in either of the phase III trials of imatinib mentioned above for patients with advanced GISTs.[15,16] However, it is best to inform patients of this risk before starting imatinib and monitor clinically for signs of heart failure or left ventricular dysfunction.
Patients with GISTs that harbor a PDGFRA exon 18 D842V mutation should initially be given avapritinib. However, for patients whose GISTs are asymptomatic or indolent, a period of observation is reasonable to avoid treatment toxicities.
Evidence (avapritinib in patients with a PDGFRA D842V mutation):
Evidence (avapritinib in patients who did not respond to imatinib and at least one additional TKI):
If indicated, avapritinib is given at 300 mg daily. Avapritinib is teratogenic, and thus, warrants effective contraception during and up to 6 weeks after the final dose.[29] The 300 mg dose was generally well-tolerated in the phase I NAVIGATOR study, with grade 3 to 4 toxicities including anemia, hyperbilirubinemia, fatigue, abdominal pain, diarrhea, peripheral edema, pleural effusion, and cognitive impairment.[2]
Cognitive effects must be closely monitored, with treatment changes (reductions, modifications, discontinuation) made promptly. Based on a post-hoc analysis of patients receiving 300 mg daily, grade 1 to 2 cognitive effects were seen in 37% of patients and 52% of patients older than 65 years. These effects included cognitive impairment, mood changes, sleep disorder, dizziness, hallucinations, and intracranial hemorrhage. These cognitive effects generally improved once treatment changes were made.[29]
Of note, for patients with GISTs who do not harbor a PDGFRA D842V mutation, avapritinib should not be used until imatinib and at least two additional agents (sunitinib and regorafenib) are tried. The open-label phase III VOYAGER trial demonstrated that regorafenib improved PFS more than avapritinib in patients without a PDGFRA D842V mutation.[28]
In the case of tumor progression (or intolerance to imatinib), data support second-line therapy with either imatinib dose escalation to 800 mg per day (as described above) or sunitinib.[16,21] Sunitinib is given at a dose of 50 mg daily in a 4-weeks-on/2-weeks-off regimen or a daily dose of 37.5 mg.[30] As with imatinib, the response to sunitinib is evaluated with CT, MRI, or 18F-FDG PET, and treatment is usually continued indefinitely in the absence of disease progression or unacceptable toxicity.[3,4,30-36]
Evidence (sunitinib):
The response to sunitinib is also influenced by the molecular profile of the GIST. Based on a phase I/II study of 97 patients, the highest clinical benefit rate, PFS benefit, and OS benefit were seen in patients with KIT exon 9 mutations, compared with patients with KIT/PDGFRA wild-type or KIT exon 11 mutations.[33]
Common side effects associated with sunitinib include the following:[30,37]
Less frequent toxicities include bleeding, fever, and hand-foot syndrome.[30] Therapy with sunitinib may be cardiotoxic. In a retrospective phase I/II study evaluating the efficacy of sunitinib in patients with imatinib-resistant metastatic GISTs, 8% of patients who received repeated cycles of sunitinib experienced congestive heart failure, while 47% of patients developed hypertension (>150 per 100 mm Hg). Reductions in left ventricular ejection fraction were seen in at least 10% to 28% of patients.[38]
The FDA has approved regorafenib for the treatment of GISTs that are refractory to first-line therapy. Regorafenib is a multikinase inhibitor with activity against KIT, PDGFRA, and VEGFR, among others. Regorafenib has demonstrated anti-GIST activity in phase II and phase III studies.[39,40]
Evidence (regorafenib):
Ripretinib is indicated for patients with advanced GISTs who have disease progression on (or are intolerant to) three or more TKIs, including imatinib. It works as a switch control inhibitor with multiple targets, including KIT exons 9, 11, 13, 14, 18, and it stabilizes the KIT molecule in its active form.
Based on the toxicity profile of ripretinib, a baseline echocardiogram or multigated acquisition (MUGA) scan should be obtained, and blood pressure and clinical signs of heart failure should be serially monitored. Dermatologic exams are warranted, given the association with the development of cutaneous cancers and hand-foot syndrome. Ripretinib is teratogenic and warrants concomitant effective contraception. It should also not be given perioperatively (1 week before or 2 weeks after surgery) because of the risk of delayed wound healing.[41,42]
Evidence (ripretinib):
Nilotinib is a second-generation TKI with similar targets to imatinib. A phase III study of nilotinib versus best supportive care in imatinib- and sunitinib-resistant GISTs showed some PFS benefit based on local assessment but no PFS benefit based on central assessment. Post-hoc analysis did reveal a modest but significant median OS difference of 4 months.[44]
Sorafenib is a multitarget kinase that is similar in structure and mechanism to regorafenib. A phase II trial of patients with imatinib- and sunitinib-resistant GISTs showed that sorafenib offered potential benefit, with a disease control rate of 68% and a median PFS of 5 months.[45]
Pazopanib inhibits VEGF signaling and showed modest PFS benefit when compared to best supportive care in a small phase II trial of patients with imatinib- and sunitinib-resistant GISTs. However, pazopanib had a high rate of toxicity.[46]
Patients without KIT or PDGFRA mutations, such as SDH-deficient and NF1-related GISTs, do not benefit from initial TKI treatment with imatinib. However, these patients may have modest response to sunitinib and regorafenib.[47] These tumors tend to have a relatively indolent course, and optimal management of these patients remains unknown. Thus, patients should be encouraged to enroll in a clinical trial, if available.
Surgery may be added to medical therapy for selected patients with GISTs in an effort to delay or prevent recurrence, although the benefit of this therapeutic approach in patients with metastatic GISTs has yet to be proven in a randomized clinical trial.
Evidence (surgery):
Overall, the indications for surgery in the management of metastatic or recurrent GISTs include the following:[3]
Stable disease and limited disease progression identify subsets of patients with advanced disease that are selected for relative disease stability. Therefore, the favorable outcomes that have been noted in case series may be principally the result of selection bias rather than true benefit from surgery.
The median time to the development of secondary resistance to imatinib has been about 2 years.[12] Therefore, it is suggested that surgery for metastatic or recurrent disease in patients receiving imatinib/sunitinib be performed before 2 years. Most experts would recommend considering surgery after 6 to 12 months of disease stability with TKI therapy.[3] Drug therapy may be continued after surgery.
Patients who have generalized disease progression while receiving standard therapies, or with certain molecular subtypes (i.e., SDH-deficient or NF1-related GISTs) may benefit from enrolling in clinical trials. These patients should be referred to specialized multidisciplinary research centers.
Use our advanced clinical trial search to find NCI-supported cancer clinical trials that are now enrolling patients. The search can be narrowed by location of the trial, type of treatment, name of the drug, and other criteria. General information about clinical trials is also available.
Eventual development of resistance to imatinib, sunitinib, and regorafenib is nearly universal. There is no standard therapy when this occurs, and patients should consider investigational therapy, such as new oral tyrosine kinase inhibitors. If eligible, patients are encouraged to participate in clinical trials.
Use our advanced clinical trial search to find NCI-supported cancer clinical trials that are now enrolling patients. The search can be narrowed by location of the trial, type of treatment, name of the drug, and other criteria. General information about clinical trials is also available.
These references have been identified by members of the PDQ Adult Treatment Editorial Board as significant in the field of gastrointestinal stromal tumor (GIST) treatment. This list is provided to inform users of important studies that have helped shape the current understanding of and treatment options for GISTs. Listed after each reference are the sections within this summary where the reference is cited.
8 to 12 weeks
Cited in:
6 to 9 months
Cited in:
1 year of imatinib
Cited in:
2 years of imatinib
Cited in:
1 year versus 3 years of imatinib
Cited in:
5 years of imatinib
Cited in:
Varying duration of imatinib
Cited in:
Imatinib
Cited in:
Cited in:
Avapritinib
Cited in:
Avapritinib versus regorafenib
Cited in:
Sunitinib
Cited in:
Regorafenib
Cited in:
Ripretinib
Cited in:
Ripretinib versus sunitinib
Cited in:
The PDQ cancer information summaries are reviewed regularly and updated as new information becomes available. This section describes the latest changes made to this summary as of the date above.
This summary was comprehensively reviewed, extensively revised, and reformatted.
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This PDQ cancer information summary for health professionals provides comprehensive, peer-reviewed, evidence-based information about the treatment of gastrointestinal stromal tumors. It is intended as a resource to inform and assist clinicians in the care of their patients. It does not provide formal guidelines or recommendations for making health care decisions.
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PDQ® Adult Treatment Editorial Board. PDQ Gastrointestinal Stromal Tumors Treatment. Bethesda, MD: National Cancer Institute. Updated <MM/DD/YYYY>. Available at: https://www.cancer.gov/types/soft-tissue-sarcoma/hp/gist-treatment-pdq. Accessed <MM/DD/YYYY>. [PMID: 26389157]
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